Lubricants containing mixed metal salts



,magnesium or strontium hydroxide.

United States Patent LUBRICANTS CONTAINING MIXED METAL SALTS Troy L. Cantrell, Drexel Hill, Pa., John G. Peters, Audulion, N.J., and Herschel G. Smith, Wallingford, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Filed Aug. 19, 1954, Ser. No.451,042

14 Claims. (Cl. 252-'40.7)

other deterioration products or contaminating materials developed during use of the lubricant. The use of detergent additives tends to'preve'nt or' retard sticking of piston rings, formation of varnish-likecoatings on pistons, cylinder wallsand moving parts and the settling out of sludge in the crankcase.

In accordance with 'our invention, We provide lubricant compositions comprising a major amount of a mineral lubricating oil and a minor amount, sufficient to confer detergency properties, of a mixed alkaline earth metal salt of 1) a naphthenic acid and (2) a condensation product of formaldehyde and a monohydric monoalkylated phenol having at least four carbon atoms in the alkyl group. These mixed metal salts are excellent additives and, in addition to conferring detergency properties, act as rust inhibitors and to a degree as bearing corrosion inhibitors. Where it is desired to improve still further the bearing corrosion inhibiting properties of the lubricant compositions ofv our invention, we add to the above-described lubricant compositions containing our detergent additives aminor amount of an alkylphenol sulfide or an alkaline earth metal salt thereof, the alkyl group of such phenol sulfides having at least four carbon atoms.

The mixed alkaline earth metal salts of our invention are prepared by forming a condensation product of' the phenol and formaldehyde and neutralizing a mixture of the condensation product and a ,naphthenic acid with an alkaline earth metal hydroxide, i.e., calcium, barium, In preparing the additives, it is not necessary to form the phenol-formaldehyde condensation product separately, nor to conduct the neutralization reaction as a separate'step, the desired prodnot being obtained simply by reacting all of the reactants simultaneously. Although the reactions proceed spontaneously at room temperatures, it is preferred to'employ moderately elevated temperatures, particularly in the last stages of the preparation. As a final step, the temperature is raised to dehydrate the product, i.e., to distill 011 the Water formed in the reaction and added with the reactants.

A dehydration temperature of about 2801 F. is suitable.

It is advantageous to employ a napththa or mineral lubricating oil as a reaction medium in order to obtain the final product in the form of a concentrated solution suitable for blending with various mineral oils.

The monohydric monoalkylated phenols employed as a reactant have at least four carbon atoms in the alkyl group. For example, such straight and branched chain alkyl groups as butyl, amyl, heptyl, octyl, nonyl, decyl, stearyl, cetyl and the long chain groups derived from parafiin wax are suitable. The alkyl groups containing from four to twelve carbon atoms form a preferred class.

ice

A preferred phenol is t'etramethylbutyl phenol, obtained by the alkylation of phenol with diisobutylerie. in known manner.

The formaldehyde employed in the condensation reaction is most conveniently used in the form of commercial aqueous formalin, containing 37 percent by weight of formaldehyde. The alkaline earth metalhydroxide is dispersed or dissolved either in water or in the aqueous formaldehyde solution.

The naphthenic acid employed in the preparation of our additives is preferably petroleum naphthenic acids. As is well known in the art, these acids are obtained by caustic alkali extraction of relatively high boiling straight run petroleum oils, such as kerosene, gas oil, lubricating oils, etc. However, our invention is not to be limited to the use of petroleum naphthenic acids since synthetic naphthenic acids, such as cyclopentyl acetic acid, 2,2,3- trimethylcyclopentyl acetic acid, hexahydrobenzoic-acid (cyclohexane carboxylic acid), cyclohexyl acetic acid, 3-

methylcyclohexyl acetic acid, cyclohexyl propionic acid,

cyclohexyl stearic acid and corresponding alkylcyclohexyl or dicyclohexyl fatty acidscan also be employed. I

The proportions of the reactants employed are not critical. Generally, the phenol and formaldehyde are employed in substantially equimolar amounts, but larger amounts of formaldehyde can be utilized if desired. A sufficient amount of the naphthenic acid is used to incorporate a significant amount of this material in the final mixed metal salt; it is preferred toemploy not less than one-sixth /6) of an equivalent and not more than one 1) equivalent of the naphthenic acid for each mol of the phenol used in thephe'nol-formaldehyde condensation. 'Enough alkaline earth metal hydroxide .issused to yield either neutral or basic mixed metal salts of the naphthenic acid and phenol-formaldehyde condensation product.

The alkyl phenol sulfides having at'least four carbon atoms in the-alkyl group are themselves known in the art, as are their neutral and basic alkaline-earth metal salts.- The phenols employed --for preparing the phenol sulfides are identical with those described hereinabove for preparing the phenol-formaldehyde condensation product. The phenol sulfides are generally preparedby' reaction of the phenol with a suitable sulfur chloride, fore'xample',

sulfur monochlon'de (=S Cl to obtain the-disulfide and sulfur dichloride (SCI to obtain the monosulfide. Other sulfur chlorides may also be used. a

The following example is illustrative of the preparation of one of the alkaline earth mixedmetal salts of'this-invention. Unless otherwise stated, all parts; are by weight.

Example I.--Into a reaction vessel, there were charged 264 parts of tetramethylbutyl phenol, 108 parts of petroleum naphthenic acids and 800 parts of a highly refined paraflinic mineral. lubricating oil'havinga-viscosity at 7 Thereafter, the solutionobtained was filtered; The

mineral oil solution of the mixed salt thus prepared had the following properties:

The following example is illustrative of the preparation 3 of an additive blend containing both the mixed metal salt described and an alkylphenol sulfide.

Example II.Into a reaction vessel, there were charged 27 parts of petroleum naphthenic acids, 166 parts of a mineral lubricating oil having a viscosity of about 155 S.U.S. at 100 F. and 66 parts of tetramethylbutyl phenol. The mixture was stirred at room temperature until uniformly blended and then a mixture consisting of 34 parts of formalin and 14.8 parts of calcium hydroxide in a water slurry were added. The reaction mass was heated to 120 F. and maintained at that temperature for one hour. With continued agitation, the temperature was gradually raised to 280 F. to dehydrate the product, which was then filtered.

In another reaction vessel, there were added 11.7 parts of sulfur dichloride to 50 pants of tetramethylbutyl phenol while maintaining the temperature at 60 F. After most of the hydrogen chloride had been evolved, the reaction mixture was refluxed for hours. The temperature was then raised slowly to 280 F. and 18 parts of the 155 S.U.S. viscosity mineral oil was added.

To prepare the final blended additive mixture of the alkaline earth mixed metal salt of the tetramethylbutyl phenol-formaldehyde condensation product and the naphthenic acid, and the tetramethylbutyl phenol monosulfide, equal parts of the mineral oil solutions of the two products were blended. This blend was heated with stirring to 160 F. and a clear solution of the additives in the mineral oil was obtained. The solution had the The petroleum naphthenic acids used in the above exarnples had the following typical inspection:

Gravity, API 13.4 Viscosity, SUS, 100 F. 520 Flash, 00, F. 285 Fire, OC, F. 310 Pour, F Sulfur, percent by wt. 1.85 Water, by dist. 0.2

Oil, percent by wt. 2.5 Neutralization value, ASTM D974, total acid No. 218

Saponification No 214 U nsaponifiable, percent 2.8 Ash, percent 0.11

While the above examples show the use of tetramethylbutyl phenol, petroleum naphthenic acids, calcium hydroxide and an alkylphenol monosulfide, it will be understood that other alkyl phenols, other naphthenic acids, other alkaline earth metal hydroxides and other alkyl phenol sulfides, all as disclosed herein, can also be employed to prepare the additives of this invention.

The alkaline earth metal mixed salts of our invention, whether or not blended with the phenol sulfides, are excellent addition agents. They are readily soluble in all types of mineral lubricating oils and can be blended with them in high proportions. They confer excellent detergent effects and rust inhibiting properties on the mineral lubricating oils in which they are incorporated, and have bearing corrosion inhibiting properties. The addition of the phenol sulfides or their alkaline earth metal salts improves the bearing corrosion inhibiting properties of the additive blend. In accordance with our invention, the alkaline earth metalrruxed salts are added to mineral oil lubricants in minor amounts, from about 0.1 ;t o about 25 percent .by weight, sufiicient .to confer improved det rgency P operties. Generally, the addition of b ut 1 to 2 p r t by weight .is i flicient t ci d the desired improvement, but for heavy duty applications larger amounts are employed. Where the phenol sulfides or alkaline earth metal salts thereof are employed along with the alkaline earth metal mixed salts, the total amount of additives employed remains in the proportion stated above. The proportion of the two additives with respect to each other is such that at least 10 percent by weight, preferably 25 percent byweight, of the phenol sulfide is employed. If desired, the phenol sulfide can be employed in larger amounts, up to 75 percent by weight of the total additive content.

The following examples illustrate the improvements obtained by the use of our additives in mineral oil lubricant compositions.

Example lII.-An improved motor lubricating oil was prepared by blending with a motor lubricating oil base 4 percent by volume of the additive concentrate prepared according to Example I. Comparative inspections and tests of the identical untreated oil and the treated oil are as follows:

Untreated Treated Oil Oil Gravity, API Viscosity, SUS:

210 F Viscosity Index- Flash, 00, F Fire, 00, F. Color, ASTM Union Appearance. Copper Strip Test, 212 F., 3 Hrs Cmpotsion Test, ASTM D (SSS-4ST Distilled a or:

Steel Rod, Appearance Area Rusted, percent Engine Test, CBC L-4:

Engine Condition Rating }iailed to {96.

Bearing Loss, Mg./Whole Bearing complete.

The additional improvement in bearing corrosion inhibiting properties obtained by the use of an alkyl phenol sulfide in the additive blend is shown in the following example.

Example IV.--A motor lubricating oil was blended with 3 percent by volume of the additive concentrate prepared according to Example II. Comparative inspections and tests of the untreated oil and treated oil are as follows:

Untreated Treated Oil Oil Gravity, API 29.1 28.6. Viscosity, SUS:

210 F 67.5.-. 09.4. Viscosity Index 106 106. Flash, 00, F 455 460. Fire, 00 Pour,

passes.

bright. 0

As shown in Example III above, the mixed alkaline earth metal salts of this invention confer eifcctive detergency properties. This is shown under the CRC L-4 test, the untreated oil failing to complete the test. As shown in Example IV, the addition of the alkyl phenol sulfide additive materially reduces the hearing loss. it is also to be noted that, in both Examples III and IV, improved rust inhibiting properties were obtained, as shown under the corro i n te Similarly effective lubricant compositions are obtained in accordance with the invention by substituting for the specific additives of Examples DI and IV other specific additives prepared from the other specific reactants shown herein. The above examples are given by way of illustration only and are not intended to limit the invention.

While a mineral lubricating oil composition has been shown in the above examples, the invention is not to be limited thereto but comprises all mineral oil lubricants to which the additives of this invention are added, such as greases and the like. As is known in the art, other additives in addition to those of our invention can also be employed. Such additives include pour point depressants, viscosity index improvers, antifoam agents, coloring agents, thickeners and the like.

We claim:

1. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sufiicient to confer detergency properties, of a mixed alkaline earth metal salt of a naphthenic acid and a condensation product of formaldehyde and a monohydric monoalkylated phenol having at least four carbon atoms in the alkyl group.

2. The composition of claim 1, wherein the naphthenic acid is petroleum naphthenic acids.

3. The composition of claim 1, wherein the alkyl group has from four to twelve carbon atoms.

4. The composition of claim 1, wherein the metal mixed salt is present in an amount of from 0.1 to 25 percent by weight.

5. The composition of claim 1, wherein the mixed salt contains not less than /6 equivalent and not more than 1 equivalent of the naphthenic acid per mol of the phenol in the condensation product.

6. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sulficient to confer improved detergency properties, of a mixed alkaline earth metal salt of petroleum naphthenic acids and a condensation product of formaldehyde and tetramethylbutyl phenol.

7. The composition of claim 6, wherein the alkaline earth metal is selected from the group consisting of calcium and barium.

8. The composition of claim 6, wherein the mixed salt contains not less than /6 equivalent and not more than 1 equivalent of the naphthenic acids per mol of the tetramethylbutyl phenol in the condensation product.

' groups of the phenol and phenol sulfide have from four to twelve carbon atoms.

11. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sufiicient to confer improved detergency and bearing corrosion inhibiting properties, of (1) a mixed alkaline earth metal salt of petroleum naphthenic acids and a condensation product of formaldehyde and tetramethylbutyl phenol; and (2) tetramethylbutyl phenol monosulfide.

12. The composition of claim 11, wherein the alkaline earth metal is selected from the group consisting of calcium and barium.

13. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sufficient to confer improved detergency and bearing corrosion inhibiting properties, of: l) a mixed alkaline earth metal salt of petroleum naphthenic acids and a condensation product of formaldehyde and teteramethylbutyl phenol; and (2) an alkaline earth metal salt of tetra methylbutyl phenol'monosulfide.

14. The composition of claim 13, wherein the alkaline earth metals of (1) and (2) are selected from the group consisting of calcium and barium.

References Cited in the file of this patent UNITED STATES PATENTS 2,367,470 Neely Jan. 16, 1945 2,372,411 Van Ess Mar. 27, 1945 2,409,687 Rogers Oct. 22, 1946 2,410,652 Griflfin Nov. 5, 1946 2,480,664 McNab Aug. 30, 1949 2,674,577 McCoy Apr. 6, 1954 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL AND A MINOR AMOUNT, SUFFICIENT TO CONFER DETERGENCY PROPERTIES, OF A MIXED ALKALINE EARTH METAL SALT OF A NAPHTHENIC ACID AND A CONDENSATION PRODUCT OF FORMALDEHYDE AND A MONOHYDRIC MONOALKYLATED PHENOL HAVING AT LEAST FOUR CARBON ATOMS IN THE ALKYL GROUP. 